1. Field
The following description relates to a semiconductor device having a buried magnetic sensor. The following description also relates to a magnetic field sensor or Hall device that is formed in buried form inside of a semiconductor substrate, wherein in a top portion of the magnetic field sensor or Hall device, analog and digital circuitry is positioned with respect to the sensor, and a related magnetic sensor or Hall sensor provide certain features.
2. Description of Related Art
A magnetic field sensing device, or Hall device, is a device that identifies a direction and a magnitude of magnetic field by use of a Hall effect. Throughout the following description, it is understood that a magnetic field sensing device and a Hall device both refer to such a device, and hence such a device is referred to only as “a magnetic field sensing device.” Likewise, as used herein, it is understood that a magnetic sensor or a Hall sensor is a sensor that senses such information in the context of a magnetic field sensing device or Hall device, and hence such a sensor is referred to only as a “magnetic sensor.” According to the Hall effect, a voltage is generated in a perpendicular direction to a magnetic field and a current when applying the magnetic field to a conductor in which a current flows. That is, the magnetic field sensing device is characterized in that two electrodes facing each other among four electrodes provide a current flow under such a circumstance that the magnetic field is applied, and that the other two electrodes facing each other provide a Hall voltage that is generated in a vertical direction with the current flow and that a Hall voltage is thus detected to determine a direction and a magnitude of the magnetic field.
Such a magnetic field sensing device is applied in a magnetic sensor such as a Digital Compass or an eCompass that provides direction data by detecting the magnetic field of the earth.
Such a magnetic sensor or provides a function that the cardinal bearing directions of north and south and east and west on the earth can be acquired by applying the Hall effect of the magnetic field sensing device with respect to the magnetic field of the earth. For example, such a magnetic sensor may be used in a portable digital apparatus such as a smartphones, by being mounted to or embedded in the smartphone. When used in combination with a portable digital apparatus, by use of a mobile application, information from such a magnetic sensor is employed with respect to a map application. For example, information from the magnetic sensor may be useful for purposes not only of obtaining a bearing of the earth, but of utilizing location data.
In the magnetic sensor, analog circuitry and digital circuitry may be used together, in order to process the detected results of the magnetic field sensing device. The analog and digital circuitry refers to various types of circuits to process the signal detected by the magnetic field sensing device. For example, the circuitry may include elements such as a low noise amplifier (LNA), an automatic gain controller (AGC), an analog-digital converter (ADC), a main controller, and other electronic elements, by way of example.
As stated above, the magnetic sensor is used along with the analog and digital circuitry. To date, the analog and digital circuitry has usually been designed to be situated in a horizontal direction with respect to the magnetic field sensing device. For example, a magnetic field sensing device is formed, and analog and digital circuitry is positioned in a lateral direction of the magnetic field sensing device. Additionally, between the magnetic field sensing device and the circuits, an insulating layer or the like may be further formed, and a variety of structures for insulation between circuits may also be provided.
Consequently, these approaches present an issue that the size of the magnetic sensor itself is not able to be reduced. This issue results in a further issue that the total size of the IC chip that constitutes the magnetic sensor is not able to be reduced either.
The above-mentioned issues lead to difficulties in efforts in for making the size of variety of portable digital apparatuses smaller. That is, unless the size of magnetic field sensing device and of its related circuits are reduced themselves, as discussed above, it is difficult to reduce the size of portable digital apparatuses due to the designated positions of magnetic field sensing device and analog/digital circuits consuming a large amount of space. Furthermore, if the size of magnetic field sensing device is reduced, the sensitivity of the device regarding the earth's magnetic field or magnetic force is also decreased. Thus, it is difficult to reduce the sensitivity of the device more than a certain level.